JPH02275605A - Soft magnetic thin film - Google Patents

Abstract

PURPOSE:To obtain a high-saturation magnetic flux density and high-frequency permeability by having a composition expression of Fea, Bb, and Nc (a, b, and c indicate atom%, respectively, and B indicates at least one type out of Zr, Hf, Ti, Nb, Ta, V, Mo, and W) and specifying the composition range. CONSTITUTION:The title item is shown by a composition expression of Fea, Bb, and Nc (a, b, and c indicates atom%, respectively, and B indicates at least one type of Zr, Hf, Ti, Nb, Ta, V, Mo, and W) and the composition range is 0<b<=20, and 0<c<=22 (excluding b<=7.5 and c<=5). When the added element B exceeds 20atom% or N exceeds 22atom%, no good soft magnetic properties can be obtained. When the composition range is 69<=a<=93, 2<=b<=15, and 5<c<=22 (preferably 5.5<c<=22), better soft magnetic properties can be shown. Thus, a high saturation magnetic flux density is achieved and magnetic distortion can be reduced to 0, thus obtaining a superb soft magnetic properties of low coercive force and high permeability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soft magnetic thin film that has high saturation magnetic flux density and high frequency permeability and is suitable as a core material of a magnetic head for high-density recording and reproduction.

[Background of the invention]

For example, in magnetic recording and reproducing devices such as audio tape recorders and VTRs (video tape recorders), the density and quality of recording signals are increasing, and in response to this increase in recording density, magnetic recording media Fe in magnetic powder as
, Co, Ni, and other metals or alloys were used. A so-called metal tape or a ferromagnetic metal material was deposited directly onto the base film by vacuum thin film formation technology. So-called vapor deposition tapes have been developed and put into practical use in various fields.

[Prior art and problems to be solved by the invention] By the way, in order to exhibit the characteristics of a magnetic recording medium having a predetermined coercive force, the core material of the magnetic head must have a high saturation magnetic flux density. If the same magnetic head is to be used for reproduction, it is also required to have high magnetic permeability.

Conventionally, sendust alloy (Fe-Si-Ajj.

B s z 10 KG), Co-based amorphous alloys, etc. have been used, but Sendust alloy has a large internal stress in the film and crystal grains tend to grow, making it difficult to thicken the film.

Also, the saturation magnetic flux density Bs is about 10KG.

The saturation magnetic flux density Bs is insufficient for higher density recording than now. In addition, Co-based amorphous alloys have good properties and can be manufactured with high saturation magnetic flux density Bs, but because they crystallize at about 450°C, glass bonding cannot be performed at high temperatures when forming heads, and sufficient bonding strength cannot be obtained. The problem was that it couldn't be done.

Other soft magnetic materials include iron nitride.

Generally, it is formed into a thin film by ion beam evaporation or sputtering using iron as a target in a nitrogen-containing atmosphere. Furthermore, this thin film was sometimes heat-treated if necessary. However, it has been reported that the coercive force of this soft magnetic thin film is significantly increased by heat treatment or heating, resulting in insufficient stability of characteristics.

Japanese Unexamined Patent Publication No. 83-299219 describes the following soft magnetic thin film that attempts to improve these problems.

rFex Ny Az (However, r x+ Yr
Z represents the composition ratio as atomic %, A is SL, Aj
2゜Ta, B, Mg, Ca, Sr, Ba, Cr.

Mn, Zr, Nb, Tt, Mo, V, W, Hf.

Represents at least one of Ga, Ge, and rare earth elements. ), and the composition range is 0.5≦y≦5.
A soft magnetic thin film characterized in that 0 0.5≦2≦7,5 x+y+z−100. However, the coercive force of the soft magnetic thin film described in JP-A-83-299219 also inevitably increases due to heat treatment.

Furthermore, since it does not have -axis anisotropy, it has the disadvantage that magnetic permeability at high frequencies cannot be increased.

Although it depends on the film forming conditions, crystalline materials generally tend to become columnar crystals due to self-shadowing effect during the film deposition process, and voids are formed at one grain boundary, making them magnetically inefficient. It tends to become continuous and the soft magnetic properties deteriorate. This self-shadowing effect becomes particularly noticeable when there are steps on the base or when the film is thick, such as when manufacturing a magnetic head, and there is a problem in that sufficient characteristics cannot be obtained.

An object of the present invention is to provide a soft magnetic thin film that improves the problems of the prior art described above.

[Means to solve the problem]

According to the present invention, the above object can be achieved with the following soft magnetic thin film.

Fe3 B,, Nc (however, a, b, c are each atomic%
, B is Zr, Hf, Ti, Nb, Ta.

Represents at least one of V, Mo, and W.), and its composition range is o<b≦20, 0<C≦22 (however, b≦7.5 and C60 are excluded). ).This composition range is defined as points E and F.
, G, H, I, J in FIG.

Preferably, the composition range is 69≦a≦93 2≦b≦15 5<c≦22 is within the range of This composition range is defined as points Q, L, and L.

It is shown in FIG. 1 by U and M.

Also preferably, Fez B1. to N (but 1al
b and c each indicate atomic %, and B is Zr and Hf.

Represents at least one of Ti, Nb, Ta, V, Mo, and W. ), and its composition range is expressed by the above-mentioned three-component composition coordinate system (F e.

B, N) P (91,2,7) Q (93,2,5) R (88,7,5) S (73,12,15) T (69,12,19) U (89,9 , 22) V (7B, 5.19) This is a soft magnetic thin film characterized by being in an area surrounded by line segments connecting seven points. This composition range is defined as points P, Q, R, S
, T, U, Vl, :, shown in FIG.

The crystal grain size is preferably 300 Å or less.

[Preferred embodiment and operation]

The soft magnetic thin film of the present invention contains Fe and N, and specific additive elements B, namely Zr, Hf, TL, and Nb.

It consists of at least one or more elements of Ta, V, Mo, and W, and the king of these Fe, N, and the specific additive element B (including two or more types) is within the specific composition range.

When the composition range is in the range of 0 b≦20 and 0 c≦22 (excluding b≦7.5 and C≦5), preferably b≧0.5 and C≧0. .5.

This is because when b<o, s or c<0.5, the effect of its presence is often not exhibited.

The additive element B exceeds 2e% or less, or.

If N exceeds 22 atomic %, good soft magnetism cannot be obtained.

When the composition range is 69≦a≦93, 2≦b≦15, and 5<c≦22 (more preferably 5.5<c≦22), better soft magnetism is exhibited.

Preferably, the composition is determined at the specific points P, Q in the champion's three-component composition coordinate system (Fe, B, N).
, R, S, T, U, and V. This composition range has a small coercive force and is therefore particularly suitable for core materials of magnetic heads. Most preferably,
This is a composition range in which the coercive force is 1.50e or less (even 10e or less).

When the additive element B is Zr, the preferable composition range of the soft magnetic thin film is as follows.

F ed (Z re N, -e) +oo-d77
The range is as follows: ≦d≦88 0.3≦e≦0.38. Point W represents this composition range.

It is shown in FIG. 1 by x, y, z. These points W.

The x, y, and z coordinates are approximately as follows.

W (88,3,6,8,4) X (88,4,5& , 7.44)Y (7
7, 8, 74, 14, 26) Z (77, 6, 9, 1
8,1) That is, in this range, Fe is included in the range of 77 to 88 at.%, and the Zr content b (at.%) and the N content C (at.9
The ratio c/b of 6) is approximately 1.83 to 2.33. A soft magnetic thin film in this composition range has good soft magnetic properties (
For example, the coercive force Ha<50e) is shown.

The additive elements may be one or more kinds. For example, only Zr can be added, but some of the Zr (for example, 3 of the added Zr) can be added with other additive elements.
0 atomic %).

Further, Fe can be replaced with one or more of Co, Ni, and Ru. For example, up to about 30 atomic % of Fe constituting the soft magnetic thin film can be replaced.

The soft magnetic thin film of the present invention is obtained by: 1 obtaining an amorphous thin film having the specific composition by a vapor deposition method such as RF sputtering; It can be manufactured by crystallizing part or all of the thin film. Preferably, the amorphous thin film may be manufactured by applying a magnetic field during the heat treatment to induce uniaxial magnetic anisotropy and crystallizing part or all of the amorphous thin film.

When manufacturing the soft magnetic thin film of the present invention by the method described above,
This is because the characteristics of the soft magnetic thin film after manufacturing may differ depending on the type of substrate on which it is formed.

It is preferable to select and manufacture the substrate appropriately.

〔Example〕

(Example 1) F e,6@-y Z r7 cy ” 5.0.1
An alloy target having a composition of 0.0.15.0 (at%) was prepared, and the target was heated to a gas pressure of 0.8 in a nitrogen-containing argon gas atmosphere containing 2.5 to 12.5 mol% of nitrogen.
High frequency sputtering was performed under conditions of Pa and input power of 200 W. The saturation magnetic flux density Bs and coercive force Hc of each thin film thus obtained after heat treatment in a magnetic field were measured. Bs
and He measurements were made using an AC BH tracer (applied magnetic field 50
Hz, 250e, but if He > 25, 90
0e) (the same applies hereafter). A crystallized glass substrate (PEG3130 manufactured by CHOYA) and a single crystal sapphire substrate were used as the substrates. Further, the film thickness was approximately 0.6 Pa in all cases.

These results are shown in Table 1-A. Note that Hc is expressed as a value in the easy axis direction. In addition, for some soft magnetic thin films,
Magnetic permeability μ and magnetostriction at 5 MHz were measured. Magnetostriction was determined from the change in BH characteristics when stress was applied to the film. The results are also shown in Table 1-A.

On the other hand, FIG. 1-B shows three types of heat-treated thin films (Nα
1, 2.3) composition, saturation magnetic flux density Bs and coercive force Hc
The measurement results are shown below.

Further, FIG. 2 shows the relationship between the composition and coercive force He of the soft magnetic thin film manufactured by the method of the above-mentioned example, and the positive/negative determination of magnetostriction (when heat treated at 550° C. using a crystallized glass substrate). Furthermore, the relationship between the soft magnetic thin film manufacturing conditions such as Fe content in the Fe-Zr alloy target and N2 content in the sputtering gas, coercive force Hc, and saturation magnetostriction λ (using a crystallized glass substrate at 550°C Fig. 3 shows the case of heat treatment.

X-ray diffraction and electrical resistivity In the above examples F e 80.9 Z r 6.5 N1
Figure 4 shows the results of X-ray diffraction for thin films that were not heat-treated (as depo) and those that were heat-treated at 250°C, 350°C, 450°C, or 550°C for composition 2.6. It is shown in Table 2. According to Figure 4, the crystal grain size of the thin film heat-treated at 550°C is about 1 from the half width.
It turned out that there were 30 people. In addition, as depo
The thin film and the thin film heat-treated at 250°C are amorphous, and the thin films heat-treated at 350°C and 450°C are composed of microcrystals.

It was found that the thin film heat-treated at 550° C. consisted of further grown microcrystals. These microcrystals are thought to contribute to the soft magnetic properties of the thin film, and the generation of such microcrystals is due to the presence of N and Zr.
This is thought to be due to the existence of According to Table 2, the resistivity of this thin film decreases by increasing the heat treatment temperature.

Even when heat treated at temperatures up to 550℃.

Its value is much higher than that of pure iron, permalloy, etc.
The value is almost the same as 'e 3i alloy and Sendust. Therefore, when used as the core of a magnetic head,
Eddy current loss is small, which is advantageous.

Vickers hardness further F e 80.9 Z r 6.5 N 12.
As a result of measuring the Vickers hardness of the thin film having composition No. 8, a value of Hvw-1000 (kg/md, weight 10 g) was obtained. This value is based on sendust and Co-based amorphous alloys (Hv
-500 to 650>, and the abrasion resistance can be sufficiently improved compared to conventional ones.

BH Convex Curves Figure 5 shows BH convex curves obtained by AC BH tracers for some of the thin films in the Examples.

The sample shown in FIG.
It was heat treated for 0 minutes. As is clear from this figure, clear in-plane-axial anisotropy is induced in the thin film by heat treatment in a magnetic field. Therefore, by setting the difficult axis or direction of this thin film as the magnetization direction, the magnetic permeability at frequencies higher than I MHz can be made sufficiently high, and from this point as well, it is advantageous as a magnetic head material. Also, since this anisotropic magnetic field Hk varies from 3 to 180e depending on the composition,
The material can be selected depending on the desired magnetic permeability and the frequency range used. For example, if you want to obtain high magnetic permeability below 10 MHz, use Hk-3 to 50e.
In order to prevent the magnetic permeability from deteriorating even at higher frequencies, a composition with a higher Hk can be used.

MH convex curve 6 shows F'eso, eZr6.
The results of M H curves measured using VSM for thin films having compositions of , N1□, and 6 are shown. In the figure, (a) shows the thin film immediately after film formation (as depo).

(b) is the M of the thin film after heat treatment in a magnetic field at 550°C.
The H convex curve is shown. (Demagnetizing field correction was not performed.

However, the sample shape is φ5 mm Xt 0.63
It was μm. ) The coercive force measured using VSM is more than an order of magnitude smaller than the value determined using AC BH tracer, and (b
), it was determined to be approximately 50m0e. This value is almost the same as that of Sendust and Co-based amorphous alloys, and it can be seen that the soft magnetic properties are excellent. Also, from (b), 4πMs-
It is determined to be 14.5KG.

This value is sufficiently higher than sendust or Co-based amorphous alloys, and is advantageous as a magnetic head material for recording on high coercive force media.

The 4πMs of the thin film before heat treatment is 13.0 KG, which is slightly lower than that after heat treatment. In addition, vertical anisotropy (Hk; 4000e
), Hc is high, and soft magnetic properties are poor.

Corrosion resistance F e 801 Z r 6.5 N in Example 1 above
Corrosion resistance of the thin film having a composition of +2.6 was evaluated based on changes in surface condition after being immersed in tap water for about -1 week.

As a result, the surface condition of one sample remained mirror-like and did not change at all. For comparison + COaL 4N b
8. . Similar experiments were conducted on Zr3,6 amorphous alloy film and Fe-5i alloy (magnetic steel sheet). As a result, the Co-Nb-Zr alloy did not change at all, but F
Rust occurred on the entire surface of the e-5i alloy. From the above, it was found that the two alloy thin films of the present invention also have excellent corrosion resistance.

Table A (blank below) Table 1 B Table 2 (Example 2) Using an alloy target throat having a composition of F e 92.5 Z r 7.5, 2.5. 5.0. 7.5.10
．． Fe--Zr--N amorphous thin films having various compositions were formed on a sapphire substrate (R-plane) by high-frequency sputtering in a nitrogen-containing argon gas atmosphere containing 0 or 12.5 mol% of nitrogen, respectively.

The amorphous thin film formed on the substrate was heated to 350°C or 550°C.
A Fe--Zr--N soft magnetic thin film of the present invention was obtained by heat treatment at .degree. C. for 1 hour. Table 3 shows the composition, saturation magnetic flux density Bs, and coercive force Hc of the obtained Fe-Zr-N soft magnetic thin film.

(Comparative Example 2) Table 3 also shows the composition, saturation magnetic flux density Bs, and coercive force Hc of a heat-treated thin film obtained in the same manner as in Example 2 except that nitrogen was not contained in the atmosphere during sputtering.

(Margin below) Table 3 (Example 3) Feg. Using a target with a composition of Z r 1o (at%), a gas pressure of 0.8P in a nitrogen-containing argon gas atmosphere containing 6.0 mol% nitrogen! l, input power 40
High frequency sputtering was performed under 0W conditions to deposit Fe7s,
A s Z r 7°3N18.8 amorphous thin film was formed.

The amorphous thin film formed on the substrate was heated to 250°C.

60 minutes at 350°C, 450°C, 500°C or 550°C.

120 minutes, 180 minutes, 240 minutes, 7540 minutes,
Two soft magnetic thin films of the present invention were obtained by heat treatment in an isothermal magnetic field (1.1 kOe applied in the <ooto> direction) for 1140 minutes, 2400 minutes, or 4800 minutes. Obtained Fe
-BH characteristics of Zr-N soft magnetic thin film (measured magnetic field Hm =
25 (Oe)), coercive force Hc, and anisotropic magnetic field Hk are shown in FIG.

Figure 8 shows (a) coercive force Hc and (b
) shows the relationship between the anisotropic magnetic field Hk. Also.

FIG. 9 shows (a) the relationship between the heat treatment time t [min], the heat treatment temperature, and the coercive force Ha, and (b) the heat treatment time t [
m1n], the heat treatment temperature, and the anisotropic magnetic field Hk.

From these, the change in BH characteristics due to heat treatment temperature is 35
0 to 500℃ range, 500℃ range, and 35
It can be seen that there are differences in the three temperature ranges below 0°C.

In addition, the above F e 75.9 Z r 7.3 N16
．． 8 Amorphous thin film was heated at 250°C for 4800 minutes at 350°C.
240 minutes at 450℃ 180 minutes at 500℃
Compositions (at%) of five types of soft magnetic thin films obtained by heat treatment for 180 minutes or 1140 minutes at 550'C, Zr content (at%) and Fe content (at%) of the soft magnetic thin films
The ratio Z r /F e .

Ratio of N content (at%) to Zr content (at%) N/
Zr and BH characteristics (measured magnetic field Hm -25 (Oe))
are shown in Table 4. Each composition below is rFe91.2
(Zr・NX)8.8However, it can be expressed as X-N/Zrte.

According to Table 4, the value of N/Zr is determined at a heat treatment temperature of 250°C.
It is said that the N/Zr value is almost constant within the range of It can be estimated.

Table 4 X-ray diffraction pattern Fe-Zr-N soft magnetic thin film obtained in Example 3,
F e 75.9 Z r 7.3 N1a before heat treatment
, s X-ray diffraction pattern of amorphous thin film (as depo) (ray source CuKa ray 40 kV, 30 mA, λ-1,
5,405 people) are shown in Figure 10. This X-ray diffraction pattern will be described below.

In the case of the as-depo thin film, it shows a typical halo pattern, confirming that it is amorphous.

The position of the main peak shifts to the wide-angle side as the heat treatment temperature increases, and finally becomes 2θ-44,8' after heat treatment at 550°C and coincides with the aFe (110) peak.

At 250℃ x 4800 minutes, it becomes 2θ-43.7'.

This coincides with the Fe3Z r (440) peak.

In heat treatment from 350°C to 500°C, 2θζ is 44°, which is a F e (110) and F e s Z
r (440) corresponds to a value approximately in the middle of the peak.

The grain size determined from the half-width of the main peak using the '3cherrer formula is approximately 100°C from 250°C to 450°C.
Large, approximately 120 people at 500℃ for 180 minutes, 550℃
Approximately 170 people in 1140 minutes (approximately 1 person at 550℃ x 60 minutes)
30 people (see Example 1 and FIG. 4)) and temperature x time.

The relationship between the time of heat treatment at 550°C, the position of the main peak, and the grain size is as follows.

From this, heat treatment at 550°C shows that fine α is formed relatively quickly.
It can be seen that although the Fe phase precipitates, the crystal grains grow slightly over the course of 2 hours.

In addition, in the heat treatment at 550°C, Fe3 was newly added in addition to αFe.
Peaks thought to be Zr and ZrN were observed, and it is thought that these were finely precipitated.

(Example 4) Using a target with a composition of F e 9o Z r to (at%), conditions of gas pressure 0.8 Pa and input power 200 W in a nitrogen-containing argon gas atmosphere containing 5.0 mol% nitrogen. A Fe--Zr--N amorphous thin film was formed on the sapphire substrate (R surface) by high-frequency sputtering.

Amorphous thin film (approximately 0.8 μm thick) formed on the substrate
The temperature change in magnetization (normalized to magnetization at room temperature) was measured by VSM. The results are shown in FIG. Measurements were performed starting from room temperature and increasing the temperature at approximately 3°C/ff1In, sample B at 340°C for 120 minutes, sample at 450°C for 60 minutes, sample E at 500°C for 60 minutes.
Sample G was heated at 520℃ for 180 minutes, and sample F was heated at 550℃.
It was held for 120 minutes. After that, -3℃/1lin
Measurements were taken while the temperature was lowered to room temperature. From FIG. 11, the Curie temperature of the Fe-Zr-N amorphous thin film (as depo) before heat treatment is about 250°C, and at least 340°C.
It can be seen that when the temperature is maintained above ℃, the magnetization value increases and the Curie temperature increases. When held at 550℃ for 120 minutes.

Curie temperature is over 700℃, and heat treatment increases α
It can be seen that the temperature approaches the Curie temperature of Fe (770°C). The magnetization at room temperature is in both cases as dep
1.12 of the as-depo amorphous thin film, but almost saturated at 520-550°C.
~1.14 times.

What was learned from Examples 3 and 4 will be described for each heat treatment temperature.

(a) Before heat treatment (as depo) Structurally, it is amorphous. Soft magnetism has not been obtained,
The Curie temperature is considerably lower than that of αFe, and the magnetic moment is lower than that after heat treatment. These are possible characteristics for an Fe-based amorphous alloy. In addition, the N content is 18
．． As many as 8%.

N/Zr-2,3.

(b) 250°C heat treatment The BH properties were slightly improved compared to as deposit, with He ranging from 5 to 70e. By increasing the heat treatment time, crystallization was confirmed by X-rays after 4800 minutes.

In addition, a -axis anisotropic film (Hc -1, 40e) was obtained.

The position of the main peak is F e3 Z r (440)
It corresponds to the peak. The N content after heat treatment is a
It is no different from s depo.

(c) 350-500°C heat treatment The main peaks are F e3 Z r (400) and a
Located in the middle of the F e (110) peak, Z
A broad bulge is also seen near r N (200), indicating a complicated state. In terms of BH characteristics, Hc = 0.7 to 0.90e, Hk -9
~120e, as heat treatment time x temperature increases, Hk
tends to become larger. Although the Curie temperature changes continuously within this range, the magnetization at room temperature is 1.
It is approximately constant at 0.6 to 1.08 times. The N content after heat treatment is slightly lower at 500°C than before heat treatment, but N/
This is the region of Zrz2.

(d) The main peak of heat treatment at 550° C. clearly corresponds to the αF e (110) peak, and new peaks that appear to be Fe3Zr and ZrN also appear. From this, after heat treatment at 550°C, fine crystals of (110) oriented αFe (grain size of about 100 to 200 grains) and even finer Fe3Zr, Z
It is thought that rN etc. were precipitated. However, the Curie temperature is lower than the Curie temperature of αFe, 770° C., and this is thought to be related to the fact that the crystal grains are fine.

Hc decreases with long-term heat treatment and reaches a minimum after about 400 minutes.
After that, it increases slightly again. Hk decreases with time and becomes almost isotropic in about 250 minutes.

The N-containing Km after heat treatment depends on the heat and treatment time, and decreases to N/Z r z L after heat treatment for θσ minutes and N/Z r z 1.1 after heat treatment for 8.1140 minutes. 5
It is thought that some nitrogen is released from the sample as N2 gas due to the 50° C. heat treatment.

As described above, when an Fe-Zr-N amorphous thin film is heat-treated, the structure and properties of the resulting soft magnetic thin film vary depending on the heat treatment temperature. This also corresponds to Table 2 showing the electrical resistivity of Example 1.

The above contents are schematically shown in FIG.

(Example 5) Feg. An alloy target with a composition of Zr1° was used.

By performing high frequency sputtering in a nitrogen-containing argon gas atmosphere containing 6.0 mol% nitrogen, +
Fe 78.22'? , 3N+6.5 and F'e7
Amorphous thin films having two compositions, s and sZ r 7.3 N+6.8, were formed on sapphire substrates (R-plane), respectively. However, the former uses a φ6 inch target and the total pressure is 0.15P.
a. Sputtering was performed with an input power of 1 kV, and a total pressure of 0.6 Pa and an input power of 400 W using a φ4 inch target.

F e 76.2 Z r 7. formed on the substrate.
3 N 16.5 amorphous thin film was heat treated in a magnetic field at 550°C for 60 minutes to form r Fe77.11 Zr 7.6 N
A 14.6 soft magnetic thin film (film thickness: about 141 cm) was obtained. Further, F e 75.9 Z r 7 formed on the substrate
．． 3N 16.8 amorphous thin films were heat-treated in a magnetic field at 550° C. to obtain two soft magnetic thin films of the present invention.

The composition of the soft magnetic thin film is F e 79.2 Z r 7.5 N13.3 when the heat treatment time is 80 minutes, and F e 83.2 Z r when the heat treatment time is 1140 minutes.
It was m, o N s, s. Table 5 shows the composition, saturation magnetic flux density Bs, coercive force Hc, and anisotropic magnetic field Hk of these soft magnetic thin films obtained.

Table 1 Fe--Hf--N soft magnetic thin films (1 μm in film thickness) within the composition range specified in the present invention were obtained. Composition and saturation magnetic flux density Bs of the obtained Fe-Hf-N soft magnetic thin film.

The coercive force Hc is shown in Table 6.

(Comparative Example 3) Table 6 also shows the composition, saturation magnetic flux density Bs, and coercive force Hc of three types of heat-treated thin films obtained in the same manner as in Example 6 except that nitrogen was not contained in the atmosphere during sputtering.

(Margin below) (Example 6) F e+atr-y Hf y (y = 5.0.
By performing high frequency sputtering in a nitrogen-containing argon gas atmosphere containing 2,4,6°8.10 or 12 mol% nitrogen using an alloy target with a composition of 10.0.15.0 (at%). 1 Fe-Hf of various compositions
A -N amorphous thin film was formed on a sapphire substrate (R surface).

The amorphous thin film formed on the substrate was heated to 350°C or 550°C.
℃, heat treated in a magnetic field of 1.1 koe for 1 hour.

Table (Example 7) F ewyo-y Ta y (Y -5,0,1
By performing high frequency sputtering in a nitrogen-containing argon gas atmosphere containing 2, 4, 68.10 or 12 mol % nitrogen using an alloy target with a composition of 0, 0, 15, 0 (at%)), various An Fe--Ta--N amorphous thin film having the composition was formed on a sapphire substrate (R surface).

The amorphous thin film formed on the substrate was heated to 350°C or 550°C.
℃, heat treated in a magnetic field of 1.1 koe for 1 hour.

A Fe--Ta--N soft magnetic thin film (1 μm in film thickness) within the composition range specified in the present invention was obtained. Composition and saturation magnetic flux density Bs of the obtained Fe-Ta-N soft magnetic thin film.

The coercive force Hc is shown in Table 7.

(Comparative Example 4) Table 7 also shows the composition, saturation magnetic flux density Bs, and coercive force Hc of a heat-treated thin film obtained in the same manner as in Example 7 except that nitrogen was not contained in the atmosphere during sputtering.

(Left below) (Example 8) F eloo-y Nby (y-5,0,LO,0
, 15,0 (at%)), and by performing high-frequency sputtering in a nitrogen-containing argon gas atmosphere containing 2, 4, 6.8, or 10 mol % nitrogen. An Fe--Nb--N amorphous thin film was formed on a sapphire substrate (R surface).

The amorphous thin film formed on the substrate was heated to 350°C or 550°C.
℃, heat treated in a magnetic field of 1.1 kOe for 1 hour.

A Fe-Nb-N soft magnetic thin film (1 μm in film thickness) within the composition range specified in the present invention was obtained. Composition and saturation magnetic flux density Bs of the obtained Fe-Nb-N soft magnetic thin film.

The coercive force Hc is shown in Table 8.

(Comparative Example 5) Table 8 also shows the composition, saturation magnetic flux density Bs, and coercive force Hc of a heat-treated thin film obtained in the same manner as in Example 8 except that nitrogen was not contained in the atmosphere during sputtering.

(Left below) (Example 9) Fe- A Zr-N amorphous thin film was formed on a substrate. As a substrate, a 5i02 film-covered ferrite substrate was used, which was obtained by forming a 5i02 film on a ferrite substrate. The amorphous thin film was formed on the surface of the 5i02 film.

The amorphous thin film formed on the substrate was heated to 550°C.

Heat treated in a magnetic field (magnetic field strength 1.1 kOe) for 1 hour,
- Soft magnetic thin film with axial magnetic anisotropy (film thickness 5.9 μm)
I got it. What is the composition of the soft magnetic thin film obtained?

From the composition of a soft magnetic thin film obtained under the same conditions except that a sapphire substrate was used instead of the above substrate.

Fe 77.1+ Z r? , 6 N 14.6
estimated that.

The electrical resistivity ρ of the obtained soft magnetic thin film was 77 tlQ-cm
The Vickers hardness Hv was loOkg/-. Further, the frequency characteristics of magnetic permeability of the obtained soft magnetic thin film are shown in Fig. 13-A, and the B-H curve is shown in Fig. 13-B.

(Example 10) By performing high-frequency sputtering in a nitrogen-containing argon gas atmosphere containing 4.0 mol% nitrogen using a target with a composition of Fe (.Hf,.(ate)),
A Fe-Hf-N amorphous thin film was formed on a substrate. As the substrate, a 5i02 film-coated ferrite substrate was used, which was formed by forming a 5in2 film on a ferrite substrate. The amorphous thin film was formed on the surface of the 5i02 film.

The thickness of the amorphous thin film formed on the substrate was 4.7 μm. This was heat-treated at 550° C. for 1 hour in a magnetic field of 1.1 [keel] to obtain a soft magnetic thin film. and.

After measuring the magnetic permeability and anisotropic magnetic field Hk of this thin film, an additional heat treatment was performed for 2 hours under the same conditions as above except for another 2 hours (total heat treatment for 3 hours). Here, the magnetic permeability and anisotropic magnetic field were also measured, and an additional heat treatment was performed for 3 hours (total heat treatment for 6 hours) under the same conditions as above except for the time.

Magnetic permeability and anisotropy field Hk were measured. The compositions of the three types of soft magnetic thin films obtained were +F e 7? ,
4 Hf 7.5 N+5. + (1 hour heat treatment).

and F e12.6 Hf 7.7 N9.7 (6
time heat treatment).

The electrical resistivity ρ of the obtained soft magnetic thin film (heat treated for 6 hours) is 604 mm, and the Vickers hardness Hv is 1l100).
It was c/d. Further, the frequency characteristics of magnetic permeability of the obtained soft magnetic thin film are shown in Fig. 14-A.

The B-H curve is shown in Figure 14-B.

Also, the magnetic permeability (at I MHz) of the three heat treatment stages
μIM□ and anisotropic magnetic field Hk are shown in Fig. 14-0. FIG. 14-0 shows changes in the magnetic permeability μIll Hz and the anisotropy magnetic field Hk with respect to the heat treatment time of the Fe-Hf-N thin film.

(Example 11) By performing high-frequency sputtering in a nitrogen-containing argon gas atmosphere containing 6.0 mol% nitrogen using a target with a composition of Fess T 815 (ate), Fe-Ta-N non-containing A crystalline thin film was formed on the substrate. As the substrate, a ferrite substrate coated with a Si02 film was used, which was formed by forming an Si02 film on a ferrite substrate.

The amorphous thin film was formed on the surface of the SiO□ film.

The amorphous thin film formed on the substrate was heated to 550°C.

Heat treated in a magnetic field (magnetic field strength 1.1 koe) for 1 hour,
- Soft magnetic thin film with axial magnetic anisotropy (film thickness 5.6μra
) was obtained. What is the composition of the soft magnetic thin film obtained?

From the composition of a soft magnetic thin film obtained under the same conditions except that a sapphire substrate was used instead of the above substrate.

F e 69.8 Ta 11.5 N IL7 The electric resistivity p of the obtained soft magnetic thin film is 88t
! Q-cm, Vickers hardness Hv is 1220 kg
It was /-. In addition, the frequency characteristics of magnetic permeability of the obtained soft magnetic thin film are shown in Figure 15-A, and the B-H curve is shown in Figure 15-A.
It is shown in Figure 5-B.

〔Effect of the invention〕

As is clear from the above description, the soft magnetic thin film of the present invention has a much higher saturation magnetic flux density than Sendust alloy or amorphous soft magnetic alloy, can reduce magnetostriction to zero, and has low retention. Excellent soft magnetic properties such as magnetic force and high magnetic permeability can be obtained.

In addition, its electrical resistivity is as high as that of Sendust, and it can be given uniaxial anisotropy by heat treatment in a magnetic field, and its magnitude can be controlled by the composition and heat treatment time.
High-frequency magnetic permeability can be obtained depending on the purpose. Furthermore, since its properties do not deteriorate even after heat treatment up to 650°C, it has excellent heat resistance for glass bonding, etc., and also has high hardness and corrosion resistance.

It has high wear resistance and is a highly reliable material.

The soft magnetic thin film of the present invention can be formed as an amorphous alloy at the time of film formation and then microcrystalized by heat treatment, so step coverage is good and a mirror surface can be easily obtained during film formation, making it possible to form a multilayer film. Since coarsening of crystal grains can be prevented without depending on any means, it is possible to increase the thickness of the film.

Therefore, by using the soft magnetic thin film of the present invention, for example, as a core material of a magnetic head, it is possible to correspond to a magnetic recording medium with a high coercive force, and it is possible to achieve higher quality, higher bandwidth, and higher recording density. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing the composition range of the soft magnetic thin film of the present invention. FIG. 2 is a diagram showing the relationship between the composition of the soft magnetic thin film manufactured in the example and the coercive force Hc, and the determination of whether the magnetostriction is positive or negative. FIG. 3 is a diagram showing the relationship between the soft magnetic thin film manufacturing conditions and the coercive force Hc and saturation magnetostriction λ of the soft magnetic thin film manufactured thereby. FIG. 4 is a diagram showing the results of X-ray diffraction of thin films subjected to different heat treatment conditions. FIG. 5 is a diagram showing AC BH convex curves of thin films with one different composition. Figure 6 is. It is a figure which shows the IH curve of the thin film before and after heat treatment calculated|required by VSM. FIG. 7 is a diagram showing the BH characteristics, coercive force Hc, and anisotropic magnetic field Hk of a Fe-Zr-N soft magnetic thin film. Figure 8 shows
FIG. 3 is a diagram showing the relationship between the coercive force He and the anisotropic magnetic field Hk of the Fe-Zr-N soft magnetic thin film obtained with respect to the heat treatment time t. Figure 9 shows heat treatment time t, heat treatment temperature, and coercive force Hc.
relationship with. and FIG. 7 is a diagram showing the relationship between heat treatment time t, heat treatment temperature, and anisotropic magnetic field Hk, respectively. FIG. 1O is a diagram showing X-ray diffraction patterns of a Fe-Zr-N soft magnetic thin film and an amorphous thin film before heat treatment. Figure 11 is. FIG. 3 is a diagram showing temperature changes in magnetization of a Fe-Zr-N soft magnetic thin film. FIG. 12 is a diagram showing estimation of the characteristics of a soft magnetic thin film obtained by heat treatment time t and heat treatment temperature. 1st
FIG. 3-A, FIG. 14-A, and FIG. 15-A are diagrams showing frequency characteristics of magnetic permeability of two soft magnetic thin films according to an embodiment of the present invention. Figure 13-B, Figure 14-B and Figure 15-
Figure B is a diagram showing AC BH convex curves in the easy axis direction (upper stage) and hard axis direction (lower stage) of a soft magnetic thin film according to an embodiment of the present invention, respectively, and B is an arbitrary unit. Figure 14-0 is. F vs. heat treatment time of Fe-Hf-N amorphous thin film
FIG. 3 is a diagram showing changes in magnetic permeability μm41 Hz and anisotropic magnetic field Hk of an e-Hf-N soft magnetic thin film. Figure 12 Heat treatment time og Figure 13-A Figure 14-0 Heat treatment time [time] Figure 14-A Frequency [MHz] Figure 15-A Figure 14-B Figure 15-B Oral procedure amendment ( Sword March 22, 1990

Claims (4)

[Claims] (1) Fe_aB_bN_c (however, a, b, c each indicate atomic %, B is Zr, Hf, Ti, Nb, Ta, V
, Mo, and W. ), and the composition range is 0<b≦20 and 0<c≦22 (excluding b≦7.5 and c≦5). (2) The soft magnetic thin film according to claim 1, wherein the composition range is 69≦a≦93 2≦b≦15 5<c≦22. (3) Fe_aB_bN_c (however, a, b, c each indicate atomic %, B is Zr, Hf, Ti, Nb, Ta, V
, Mo, and W. ), and its composition range is P (91,2,7) Q (93,2,5) R (88, 7,5) S (73,12,15) T (69,12,19) U (69,9,22) V (76,5,19) This is the range surrounded by the line segment connecting the 7 points. A soft magnetic thin film characterized by: (4) The soft magnetic thin film according to any one of claims 1 to 3, characterized in that the crystal grain size is 300 Å or less.